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Frequent Mistakes When Conducting HAZOP and How To Avoid Them




A Hazard and Operability (HAZOP) study is a structured and systematic review of an existing process or operation to identify and evaluate risks to personnel or equipment. A HAZOP study is done to review and pick up design and engineering issues that may otherwise not have been known. The HAZOP team lists potential causes and consequences from these issues. If existing safeguards fail to meet the criteria, the team recommends the action be taken to reduce the risk. HAZOP’s meticulous approach requires a team with relevant expertise, and here are the three common mistakes when doing a HAZOP study.


  • Poor time management

One of the most common mistakes of a HAZOP study includes not allocating enough time for it. As planning for the schedule is done neither by the HAZOP facilitator or team, there is a lack of knowledge on the processes involved or expertise when doing so. It should be done by someone who is knowledgeable and understands all the risks involved in a HAZOP study. Ideally, the HAZOP schedule should include some flexibility and planned according to the number of processes and stages involved.


  • Incomplete process safety information

Prior to doing HAZOP, all prerequisite process safety information needs to be complete and updated. A common mistake during HAZOP is that the information are out-of-date or incomplete, which increases the timeline and affects the quality of HAZOP. This includes piping and instrumentation diagrams (P&IDs) and current standard operating procedures (SOPs). If the HAZOP is conducted by an external facilitator, it is the responsibility of the owner of the process to verify the integrity of the process safety information.


  • Incorrect size of HAZOP team

The size of the HAZOP team affects the quality of the study. A team too large may cause the discussions to be disruptive and discussions may run for too long, while a team too small may lack the relevant expertise for the team to properly evaluate the process hazards and controls. The ideal size should be between five to seven people, excluding the HAZOP facilitator.


Advanced HAZOP Masterclass is a 2-day course held from 15 – 16 October 2018 (Singapore) and 17-18 October 2018 (Kuala Lumpur), where refresher topics of HAZOP such as bowties, swiss cheese and LOPA, the human factors and the limitation of HAZOP and its operability are discussed. Participants will learn about the roles and responsibility of HAZOP team members and leaders, as well as participate in exercises on how to pick the best approach to safety study depending on different scenarios. For more information, please visit us at  or contact us at


 Interested to read other HAZOP articles? Check out: What is HAZOP?


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